function Stack() {
    this.data = [10];
    this.size = 0;
}
Stack.prototype.pop = function () {
    var curr = this.data[this.size - 1];
    this.size = this.size - 1;
    return curr;
}
Stack.prototype.push = function (data) {
    this.data[this.size] = data;
    this.size += 1;
}
var st = new Stack();
st.push(1)
st.push(2)
st.push(3)
var data = st.pop()
console.log(data);
console.log(st);
